Many known wheel chairs are disclosed such as those disclosed in DE 3742547, GB 2101540, U.S. Pat. Nos. 4,648,619, 4,721,321, 4,730,842, 5,28,183, 5,522,404, 6,296,265, 6,338,496, 6,345,833, 6,499,756, 6,499,762, 6,648,359, and 5,522,404. DE 3,742,547, U.S. Pat. Nos. 4,648,619, 4,721,321, 4,730,842, and 6,338,496 discloses wheel chairs wherein the rear wheels are pivotably connected one of multiple holes on the side frames. U.S. Pat. No. 4,721,321 discloses that the arm rests are connected to a quick release device on a side of the seat frame. U.S. Pat. Nos. 6,338,496 and 6,648,359 disclose that the arm rests are threaded to the holes in the back rest frame, the height of the arm rest can be adjusted, however, cannot be tilt. U.S. Pat. Nos. 4,730,842, 4,721,321, and 6,338,496 disclose that the front frame includes extension tubes for connecting the foot rests. U.S. Pat. Nos. 6,338,496 and 6,499,756 disclose that the foot rests are connected to the wheel frames by threaded sleeves, U.S. Pat. No. 6,499,756 employs a spring to position the foot rests which is allowed to be pivotable. U.S. Pat. Nos. 4,648,619, 4,721,321, 5,328,183, 6,499,762 and GB 2101540 disclose that the folding device cannot be disengaged from the frames. U.S. Pat. No. 5,522,404 uses a safety belt. U.S. Pat. No. 4,730,842 discloses that the arm rests are rotatably connected to the backrest frame by a special member and the foot rests can be rotatably folded but cannot provide comfortable use. The seat pad is connected to the frame by Velcro strips and the width of the wheel chair can be adjusted but cannot be folded. It is noted that the conventional wheel chairs cannot provide a wide range of adjustments to meet needs of different users. Some parts cannot be independently separated from the main frame so that a huge assembly has to be replaced in maintenance, and this spends a lot.
The present invention intends to provide a wheel chair which is composed of several units which are able to be adjusted according to the needs of different users.